// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#if V8_TARGET_ARCH_X64

#include "src/deoptimizer.h"
#include "src/macro-assembler.h"
#include "src/objects-inl.h"
#include "src/register-configuration.h"
#include "src/safepoint-table.h"

namespace v8 {
namespace internal {

#define __ masm->

    void Deoptimizer::GenerateDeoptimizationEntries(MacroAssembler* masm,
        Isolate* isolate,
        DeoptimizeKind deopt_kind)
    {
        NoRootArrayScope no_root_array(masm);

        // Save all general purpose registers before messing with them.
        const int kNumberOfRegisters = Register::kNumRegisters;

        const int kDoubleRegsSize = kDoubleSize * XMMRegister::kNumRegisters;
        __ subq(rsp, Immediate(kDoubleRegsSize));

        const RegisterConfiguration* config = RegisterConfiguration::Default();
        for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
            int code = config->GetAllocatableDoubleCode(i);
            XMMRegister xmm_reg = XMMRegister::from_code(code);
            int offset = code * kDoubleSize;
            __ Movsd(Operand(rsp, offset), xmm_reg);
        }

        const int kFloatRegsSize = kFloatSize * XMMRegister::kNumRegisters;
        __ subq(rsp, Immediate(kFloatRegsSize));

        for (int i = 0; i < config->num_allocatable_float_registers(); ++i) {
            int code = config->GetAllocatableFloatCode(i);
            XMMRegister xmm_reg = XMMRegister::from_code(code);
            int offset = code * kFloatSize;
            __ Movss(Operand(rsp, offset), xmm_reg);
        }

        // We push all registers onto the stack, even though we do not need
        // to restore all later.
        for (int i = 0; i < kNumberOfRegisters; i++) {
            Register r = Register::from_code(i);
            __ pushq(r);
        }

        const int kSavedRegistersAreaSize = kNumberOfRegisters * kSystemPointerSize + kDoubleRegsSize + kFloatRegsSize;

        __ Store(
            ExternalReference::Create(IsolateAddressId::kCEntryFPAddress, isolate),
            rbp);

        // We use this to keep the value of the fifth argument temporarily.
        // Unfortunately we can't store it directly in r8 (used for passing
        // this on linux), since it is another parameter passing register on windows.
        Register arg5 = r11;

        // The bailout id is passed using r13 on the stack.
        __ movq(arg_reg_3, r13);

        // Get the address of the location in the code object
        // and compute the fp-to-sp delta in register arg5.
        __ movq(arg_reg_4, Operand(rsp, kSavedRegistersAreaSize));
        __ leaq(arg5, Operand(rsp, kSavedRegistersAreaSize + kPCOnStackSize));

        __ subq(arg5, rbp);
        __ negq(arg5);

        // Allocate a new deoptimizer object.
        __ PrepareCallCFunction(6);
        __ movq(rax, Immediate(0));
        Label context_check;
        __ movq(rdi, Operand(rbp, CommonFrameConstants::kContextOrFrameTypeOffset));
        __ JumpIfSmi(rdi, &context_check);
        __ movq(rax, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
        __ bind(&context_check);
        __ movq(arg_reg_1, rax);
        __ Set(arg_reg_2, static_cast<int>(deopt_kind));
        // Args 3 and 4 are already in the right registers.

        // On windows put the arguments on the stack (PrepareCallCFunction
        // has created space for this). On linux pass the arguments in r8 and r9.
#ifdef _WIN64
        __ movq(Operand(rsp, 4 * kSystemPointerSize), arg5);
        __ LoadAddress(arg5, ExternalReference::isolate_address(isolate));
        __ movq(Operand(rsp, 5 * kSystemPointerSize), arg5);
#else
        __ movq(r8, arg5);
        __ LoadAddress(r9, ExternalReference::isolate_address(isolate));
#endif

        {
            AllowExternalCallThatCantCauseGC scope(masm);
            __ CallCFunction(ExternalReference::new_deoptimizer_function(), 6);
        }
        // Preserve deoptimizer object in register rax and get the input
        // frame descriptor pointer.
        __ movq(rbx, Operand(rax, Deoptimizer::input_offset()));

        // Fill in the input registers.
        for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
            int offset = (i * kSystemPointerSize) + FrameDescription::registers_offset();
            __ PopQuad(Operand(rbx, offset));
        }

        // Fill in the float input registers.
        int float_regs_offset = FrameDescription::float_registers_offset();
        for (int i = 0; i < XMMRegister::kNumRegisters; i++) {
            int src_offset = i * kFloatSize;
            int dst_offset = i * kFloatSize + float_regs_offset;
            __ movl(rcx, Operand(rsp, src_offset));
            __ movl(Operand(rbx, dst_offset), rcx);
        }
        __ addq(rsp, Immediate(kFloatRegsSize));

        // Fill in the double input registers.
        int double_regs_offset = FrameDescription::double_registers_offset();
        for (int i = 0; i < XMMRegister::kNumRegisters; i++) {
            int dst_offset = i * kDoubleSize + double_regs_offset;
            __ popq(Operand(rbx, dst_offset));
        }

        // Remove the return address from the stack.
        __ addq(rsp, Immediate(kPCOnStackSize));

        // Compute a pointer to the unwinding limit in register rcx; that is
        // the first stack slot not part of the input frame.
        __ movq(rcx, Operand(rbx, FrameDescription::frame_size_offset()));
        __ addq(rcx, rsp);

        // Unwind the stack down to - but not including - the unwinding
        // limit and copy the contents of the activation frame to the input
        // frame description.
        __ leaq(rdx, Operand(rbx, FrameDescription::frame_content_offset()));
        Label pop_loop_header;
        __ jmp(&pop_loop_header);
        Label pop_loop;
        __ bind(&pop_loop);
        __ Pop(Operand(rdx, 0));
        __ addq(rdx, Immediate(sizeof(intptr_t)));
        __ bind(&pop_loop_header);
        __ cmpq(rcx, rsp);
        __ j(not_equal, &pop_loop);

        // Compute the output frame in the deoptimizer.
        __ pushq(rax);
        __ PrepareCallCFunction(2);
        __ movq(arg_reg_1, rax);
        __ LoadAddress(arg_reg_2, ExternalReference::isolate_address(isolate));
        {
            AllowExternalCallThatCantCauseGC scope(masm);
            __ CallCFunction(ExternalReference::compute_output_frames_function(), 2);
        }
        __ popq(rax);

        __ movq(rsp, Operand(rax, Deoptimizer::caller_frame_top_offset()));

        // Replace the current (input) frame with the output frames.
        Label outer_push_loop, inner_push_loop,
            outer_loop_header, inner_loop_header;
        // Outer loop state: rax = current FrameDescription**, rdx = one past the
        // last FrameDescription**.
        __ movl(rdx, Operand(rax, Deoptimizer::output_count_offset()));
        __ movq(rax, Operand(rax, Deoptimizer::output_offset()));
        __ leaq(rdx, Operand(rax, rdx, times_system_pointer_size, 0));
        __ jmp(&outer_loop_header);
        __ bind(&outer_push_loop);
        // Inner loop state: rbx = current FrameDescription*, rcx = loop index.
        __ movq(rbx, Operand(rax, 0));
        __ movq(rcx, Operand(rbx, FrameDescription::frame_size_offset()));
        __ jmp(&inner_loop_header);
        __ bind(&inner_push_loop);
        __ subq(rcx, Immediate(sizeof(intptr_t)));
        __ Push(Operand(rbx, rcx, times_1, FrameDescription::frame_content_offset()));
        __ bind(&inner_loop_header);
        __ testq(rcx, rcx);
        __ j(not_zero, &inner_push_loop);
        __ addq(rax, Immediate(kSystemPointerSize));
        __ bind(&outer_loop_header);
        __ cmpq(rax, rdx);
        __ j(below, &outer_push_loop);

        for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
            int code = config->GetAllocatableDoubleCode(i);
            XMMRegister xmm_reg = XMMRegister::from_code(code);
            int src_offset = code * kDoubleSize + double_regs_offset;
            __ Movsd(xmm_reg, Operand(rbx, src_offset));
        }

        // Push pc and continuation from the last output frame.
        __ PushQuad(Operand(rbx, FrameDescription::pc_offset()));
        __ PushQuad(Operand(rbx, FrameDescription::continuation_offset()));

        // Push the registers from the last output frame.
        for (int i = 0; i < kNumberOfRegisters; i++) {
            int offset = (i * kSystemPointerSize) + FrameDescription::registers_offset();
            __ PushQuad(Operand(rbx, offset));
        }

        // Restore the registers from the stack.
        for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
            Register r = Register::from_code(i);
            // Do not restore rsp, simply pop the value into the next register
            // and overwrite this afterwards.
            if (r == rsp) {
                DCHECK_GT(i, 0);
                r = Register::from_code(i - 1);
            }
            __ popq(r);
        }

        // Return to the continuation point.
        __ ret(0);
    }

    bool Deoptimizer::PadTopOfStackRegister() { return false; }

    void FrameDescription::SetCallerPc(unsigned offset, intptr_t value)
    {
        if (kPCOnStackSize == 2 * kSystemPointerSize) {
            // Zero out the high-32 bit of PC for x32 port.
            SetFrameSlot(offset + kSystemPointerSize, 0);
        }
        SetFrameSlot(offset, value);
    }

    void FrameDescription::SetCallerFp(unsigned offset, intptr_t value)
    {
        if (kFPOnStackSize == 2 * kSystemPointerSize) {
            // Zero out the high-32 bit of FP for x32 port.
            SetFrameSlot(offset + kSystemPointerSize, 0);
        }
        SetFrameSlot(offset, value);
    }

    void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value)
    {
        // No embedded constant pool support.
        UNREACHABLE();
    }

#undef __

} // namespace internal
} // namespace v8

#endif // V8_TARGET_ARCH_X64
